Top form for concrete conduits



July 28, 1959 c. BARRON TOP FORM FOR CONCRETE CONDUITS Filed Dec. 3. 19 57 2 Sheets-Sheet 2 lllll i n mm J i a ATTORNEYS.

United States Patent TOP FORM FOR C'ONCR'E'DE CONDUITS Curtis L. Barron, Sacramento, Calif. Application December 3, 1957, Serial No. 700,486 1 Claim. (Cl. 25-13 15) This invention relates to a top form for concrete conduits, of circular form, and has as its primary object the provision of an arcuate form, permitting the reinforcement of poured concrete during the formation of a circular duct or conduit, and which may be readilyremoved after the concrete of the upper portion has hardened.

An additional object of the invention is the provision of such a device which may be constructed in a plurality of sections, of a size to facilitate handling thereof, and which may be removed either individually, or in groups, in accordance with the particular constructional features.

A further object of the invention is the provision of a device of this character which is comprised of two hinged arcuate supporting sections, which are normally held in extended position, by means of a catch or the like, and provided with a central operating means, which will release the catch and simultaneously swing the two half sections towards each other about their common hinges to Withdraw the same from the hardened upper portion of the duct, and permit the longitudinal withdrawal of the supporting frame from the completed concrete structure.

Still another object of the invention is the provision of a device of this character which is sturdy and durable in construction, reliable and eflicient in operation, and relatively simple and inexpensive to manufacture, assemble and utilize.

Other objects reside in the combinations of elements, features of construction, and relationship of parts, all as will be more fully pointedout hereinafter, and disclosed in the accompanying drawings.

In the drawings:

Figure 1 is a vertical longitudinal section taken substantially along the center line 11'of Figure 3 showing one form of reinforcing frame embodying features of the instant invention shown in position on the lower portion of a conduit, preparatory to pouring the upper half thereof.

Figure 2 is a top plan view of the structure, with the cement supporting arcuate covering members removed.

Figure 3 is an enlarged transverse vertical section of a conduit partially formed, taken on line 33 of Figure 1 showing the frame or support of the instant invention in position prior to pouring of the upper half of the conduit.

Figure 4 is an enlarged longitudinal sectional view taken substantially along the line 44 of Figure 2 as viewed in the direction indicated by the arrows.

Figure 5 is an enlarged sectional view taken substantially along the line 5-5 of Figure 2 as viewed in the direction indicated by the arrows.

Figure 6 is a sectional view taken substantially along the line 6-6 of Figure 4 as viewed in the direction indicated by the arrows, on an enlarged scale.

Figure 7 is an enlarged sectional view taken substantially along the line 77 of Figure -4 as viewed in the direction indicated by the arrows.

Similar reference characters refer to similar parts throughout the several views of the drawings.

Having reference now to the drawings, there is disclosed at 10 a lower portion of a concrete form having a central opening 11 therein, forming the lower portion of a conduit or similar device for the conduction of fluids. In its finished form the central opening 11 will'be circular in cross section. As best shown in Figure 3 the concrete duct portion 10 is positioned on the bottom of the ditch 12 and may be formed with conventional formers.

In the construction of such circular ducts, formed in two pieces, various types of removable inner supports or forms to support poured concrete prior to hardening have hitherto been provided. However these have been characterized uniformly by difliculty in removal, after the concrete has hardened, and this is particularly true in small ducts, where access to the form by a workman is difficult or impossible.

The form of the instant invention provides a sturdy support for the upper portion of the concrete duct during the pouring, and may be readily removed after the concrete of a particular section has hardened, from the outside of the conduit.

The form comprising the instant invention is generally indicated at 15, and comprises two transversely arcuate sections 16, hinged together at their center as by hinges 17 of any desired conventional construction. The segment 16 may be of any desired size, in accordance with the diameter of the circular conduit constructed, and comprise any degree of are from a semi-circle to a quarter circle. The lower edge of each section 16 is provided with a protruding flange 18, which is adapted to rest on the lip of the previously formed lower portion 10 of the conduit.

Means are provided for normally holding the arcuate segment 16 in extended position, and take the form of oppositely disposed pairs of sockets 19, adjacent the lower portion of each segment, which are adapted to receive the ends of a releasable bracing bar generally indicated at 20. Each bracing bar is comprised of two segments 21 and 22. The segment 21 is preferably comprised of solid material, and has a rounded end 23 adapted to seat in one of sockets 19, and includes at its other end a cup or socket 24. The socket 24 is adapted to receive a hemispherical detent 25 carried at the end of section 22. The section 22 includes an internally cup shaped and internally threaded sleeve 26, which contains the threaded end 27 of a tubular member 28, which contains a spring 29, the tubular section 28 being rotatable within the section 27 in order to permit adjustment of the tension of the spring 29. The other end of the spring 29 engages a ball detent 30, which is suitably retained in the end of tubular section 28, and which is adapted to engage in the opposite detent 19. Means 31 comprising a protruding portion are provided for the relative rotation of members 28 and 22 to vary the tension on the spring 29.

A pair of chains 33 and 34 connect the sections 21 and 22 respectively to a ring 35, which is permanently aflixed to a longitudinally extending rod or cable 36, which is provided at one end with a hook 37, and its other with an eye 38. The hooks 37 may be engaged in the eye 38 of an adjacent section, or correspondingly the eye 38 may be engaged by the hook 37 of an adjacent section, for a purpose and in a manner to be more fully described hereinafter. The member 35 is fixed to the cable 36 in a manner to be more fully described hereinafter.

Adjacent each brace 20 are a pair of crossed cables 40, each having one end secured, by a welding 41 to one of arcuate segments 16, at an intermediate point thereof.

Each cable 40 extends from its point of attachment 41 on one segment to a ring '42 fixedly secured to the inner wall of the opposite segment 16, and thence to an eye 43 carried by a circular member 44, the latter being slidably mounted on the cable or rod 36. As best shown in Figure 6 the member 44 is comprised of two separable half sections 45, provided with bores, through which extends screws 46, the bores ofone segment 45 being threaded whereby the screws may be tightened. A relatively large semi-circular opening 47 is provided in the abutting face of each segment to surround the cable or rod 36, to permit the sliding movement of the member 44 thereon.

A circular stop member 50 is secured to the cable 36 between the slidable member 43, and the end of the rod 01- cable 36 which carries the eye 38. The stop member 50 also comprises a pair of separable semi-circular seg ments 51, provided with aligned bores for the reception of screws 52, the bores of one section being threaded to permit tightening of the screws. The confronting face of each semi-circular segment 51 is provided with a semicircular channel or recess 53, of lesser diameter than the rod or cable 36, whereby the member 50 may be relatively tightly clamped to the member 36 to provide a stop. It may here be pointed out that the-member s 35 are substantially identical in construction with the stops 50, with the exception of the fact that they are provided with eyes 54 for the accommodation of the chains 33 and 34.

From the foregoing the use and operation of the device should now be readily understandable. A lower section of concrete is first poured, and allowed to harden. The form 15 of the instant invention is then extended'and braced by means of the bars 20, it being noted that there are at least two brace bars 20 to each section, preferably adjacent the opposite ends thereof, and the flanges 17 fitted over the edges of the previously hardened concrete 10. The top of the conduit or the like is then poured and allowed to harden. After the top portion of the concrete has hardened, the rod 36 is pulled in the direction of the eye 38, the eye 38 being preferably positioned at the open or unfinished end of the conduit. Such pulling action serves to move each member 35 against its adjacent brace 20, dislodging the same, by means of the releasable spring pressed detent 30 from its associated detents 19, the two segments falling free. This permits the collapsing of the two arcuate frame segments 16 about their hinges 17, and in the event that they adhere to the inner side of the newly formed upper portion of the conduit the members 44 are pulled forwardly until they engage the stops 50. Additional pulling on the rod, will pull the opposed rings 42 toward each other, by tightening of the cables 40, and this in turn will pull the segments 16 away from the conduit, permitting the entire assembly to fall to the bottom of the conduit, from which it may be readily withdrawn.

From the foregoing it will now be seen that there is herein provided a device which accomplishes all of the objects of this invention, and others, including many advantages of great practical utility and commercial importance.

As many embodiments may be made of this inventive concept, and as many modifications may be made in the embodiment herein before shown and described, it is to be understood that all matter herein is to be interpreted merely as illustrative and not in a limiting sense.

I claim:

Brace and release means for use with a pair of elongated tr ansversely arcuate support members having hinges connecting the members along contiguous sides thereof to form an arcuate support for concrete poured thereon and means on the outer edges of said members for supporting said members upon the sides of a previously formed base portion, said brace means comprising a pair of separable segments adapted to hold theouter edges of the support members in spaced apart relation, said segments each having a rounded end adapted to be received in a cup carried by oppositely aligned sockets carried by the support members, at least one of said rounded ends comprising a spring biased ball detent, the other end of each rod being substantially flat to engage in abutting relation, one of said other ends having a detent therein and the other of said other ends having a socket for the reception of said detent, said means for releasing said members comprising a rod operable for longitudinal movement from a remote point, a ring fixed to said rod, a chain extending from said ring to each segment, a circular member slidably mounted on said rod, a cable aifixed to each side of said circular member, said cables being adapted to extend to a ring on the adjacent support member and thence across to have their ends secured to the opposite support member, and a second ring fixed to said rod forming a stop for slidable movement of said circular member, whereby a pull on said rod releases said rounded ends from their associated sockets to cause said segments to disengage, and hence permit release of said support members from. the hardened concrete.

References Citedin the file of this patent UNITED STATES PATENTS 455,605 Brooks July 7, 1891 1,079,000 Fisher Nov. 18, 1913 1,096,047 Miller May ,12, 1914 1,097,234 Kempf May 19, 1914 1,101,204 Massey June 23, 1914 2,608,420 Eck Aug. 26, 1952 2,807,071 Francis et a1. Sept. 24, 1957 

